Method of manufacturing light emitting device

ABSTRACT

A method of manufacturing a light emitting device is provided which requires low cost, is easy, and has high throughput. The method of manufacturing a light emitting device is characterized in that: a solution containing a light emitting material is ejected to an anode or cathode under reduced pressure; a solvent in the solution is volatilized until the solution reaches the anode or cathode; and the remaining light emitting material is deposited on the anode or cathode to form a light emitting layer. A burning step for reduction in film thickness is not required after the solution application. Therefore, the manufacturing method, which requires low cost and is easy but which has high throughput, can be provided.

This application is a continuation of U.S. application Ser. No.10/464,798, filed Jun. 18, 2003, (U.S. Pat. No. 6,858,464).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a technical field concerning displaydevices (hereinafter referred to as light-emitting devices) comprising,on a substrate, an element (hereinafter referred to as a light-emittingelement) having a structure comprising an anode, a cathode, and a thinfilm (hereinafter referred to as a light-emitting layer) sandwichedbetween the anode and the cathode to emit light relying upon aphenomenon called electroluminescence. The invention further relates toa technical field concerning an electronic device provided with thelight-emitting device as an video display portion.

2. Description of the Related Art

In recent years, it has been urged to develop a light-emitting devicereferred to as an organic EL panel, an organic light-emitting diode(OLED) and the like as video displays. This is realized by generating alight-emitting phenomenon called electroluminescence by recombiningholes and electrons in the light-emitting layer formed between anelectrode (hereinafter referred to as an anode) for injecting holes andan electrode (hereinafter referred to as a cathode) for injectingelectrons, and by controlling on/off of light emission to displayimages.

A thin organic film is mainly used as a light emitting layer used forthe light-emitting device. An evaporation method had been a favoredmethod for forming the thin organic film by using a low molecular weightmaterial. At present further, however, a method has been vigorouslydeveloped for forming the light-emitting layer comprising a highmolecular weight material used for the light-emitting device by applyinga solution, such as by a spin-coating method, an ink jet method or aprinting method. In particular, formation of a thin organic film by theink jet method is already approaching a practicable level, and its basictechnology has been disclosed in, for example, JP 10-012377.

The ink jet method is technology accomplished by applying the ink jetmethod that has heretofore been used in the printers to the formation ofthin films, by using, instead of an ink, a solvent such as water or analcohol in which is dissolved or dispersed a solute that is a materialof the organic thin film, and applying a droplet solution to each of thepixels. As a matter of course, since a droplet solution attached ontopixels (which are pixel electrodes provided in the respective pixels, infact) includes a lot of solvent ingredients, an additional step forvaporizing the solvent ingredients (hereinafter referred to as a stepfor firing) is required in order to remove the solvent ingredients. Thatis, after the droplet solution is applied by the ink jet method, each ofthe pixels is heated entirely to vaporize the solvent ingredients,thereby reducing the thickness of remaining solute (which is a materialfor an organic thin film).

Such step for firing is generally conducted in an electric heatingfurnace, therefore it causes a reduction of throughput. Further, it ishard to vaporize the solvent ingredients at low temperature, and whenthe solvent ingredients are remained in a thin film, the ingredients arevaporized with time to cause a degassing phenomenon, thereby causingdeterioration of the organic thin film. Furthermore, deterioration of alight emitting element is caused. In addition, when heating temperatureis increased in order to remove the solvent ingredients completely, thecomposition of the organic thin film that has low heat resistance isdestroyed.

As set forth above, although the film formation method using the ink jetmethod has the advantage of being able to manufacturing a light emittingdevice at low cost, through a simple method and featuring a highthroughput, the film formation method is a technique that leaves to beimproved at a point in which the step for firing is necessary.

SUMMARY OF THE INVENTION

This invention was accomplished in view of the above problems, andprovides a technique in which the step for firing is not necessary withrespect to the method for forming a thin film by applying a solution.Furthermore, the present invention provides a method of manufacturing alight emitting device at low cost, through a simple method and featuringa high throughput by applying aforementioned technique to the formationof the light emitting device.

According to the present invention, it is characterized in that: asolution containing a light emitting material is ejected to a pixelelectrode (anode or cathode) under reduced pressure; and thelight-emitter composition is deposited on the pixel electrode to form atleast a layer of a thin film which constitutes a light emitter. At thistime, it may be that: a solvent in the solution is volatilized until thearrival of the solution at the pixel electrode; and the remaininglight-emitter composition is deposited on the pixel electrode to form atleast a layer of a thin film which constitutes a light emitter. Further,it may be that: the pixel electrode is previously heated (at a roomtemperature (typically 20° C.) to 300° C., preferably 50 to 200° C. inconsideration of heat resistance of the light emitter) to thereby startvolatilization of a solvent in the solution simultaneously with thearrival of the solution at the pixel electrode; and the remaininglight-emitter composition is deposited on the pixel electrode to form atleast a layer of a thin film which constitutes a light emitter. In anycase, the characteristic of the present invention resides in a pointthat the solvent component is volatilized simultaneously with theformation of at least the layer of the thin film which constitutes thelight emitter, which eliminates or shortens a burning step that has beenrequired in the prior art.

In the present invention, the light emitter indicates an organiccompound, inorganic compound, or laminate body which contributes to acarrier injecting layer (hole injecting layer or electron injectinglayer), carrier transporting layer (hole transporting layer or electrontransporting layer), carrier blocking layer (hole blocking layer orelectron blocking layer), light emitting layer, and other recombinationof carriers. Further, the light-emitter composition indicates acomposition that serves as a material for the light emitter, and iscomprised of either the organic compound or the inorganic compound. Thelight-emitter composition is roughly divided into a light emittingmaterial and a carrier (hole or electron) transporting material.

The light emitting material is a material that causes a light emissionphenomenon with electroluminescence through injection of holes andelectrons. The above-described light emitting material is found in boththe categories of inorganic compounds and organic compounds. However, itis preferable that the organic compound is used in the solution applyingmethod as in the present invention. Further, as the light emittingmaterial, a material that emits fluorescence through singlet excitationand a material that emits phosphorescence through triplet excitation maybe used. In addition, the hole transporting material is a material withwhich holes move easily, and the electron transporting material is amaterial with which electrons move easily.

The reduced pressure indicates a pressure lower than an atmosphericpressure, and may be set at 1×10² to 2×10⁴ Pa (preferably, 5×10² to5×10³ Pa) in an atmosphere filled with an inert gas such as nitrogen orrare gas (hereinafter, referred to as inert atmosphere) or set at 1 to5×10⁴ Pa (1×10² to 1×10³ Pa) in vacuum. By setting the reduced pressure,a solvent is always volatilized from a droplet until the droplet ejectedin the atmosphere reaches the pixel electrode, and the volume of thedroplet is gradually reduced. Then, most of the solvent has beenvolatilized at the point of time when the droplet reaches the pixelelectrode, and the film formation is completed simultaneously with thearrival of the droplet. That is, this is superior to the prior art in apoint that a heating step such as a burning step is not required afterthe solution application.

Further, a solvent with high volatility (that is, a solvent with a highvapor pressure) may be used in order to sufficiently volatilize thesolvent before the arrival at the pixel electrode. This is because,although a period of time necessary for volatilization needs to begained by lengthening the distance between the pixel electrode and anejection opening (tip end portion of a nozzle) for the solution in thecase of the solvent with low volatility, a ballistic error of thedroplet is increased with the long distance. Alcohols such as methanoland ethanol are given as the solvents with high volatility.

Further, a solvent with a high boiling point is used instead of thesolvent with high volatility, whereby there can be eliminated, forexample, apprehension that drying of the droplet at the ejection openingcauses clogging at the tip end of the nozzle. In this case, when thepixel electrode is previously heated (at a room temperature (typically,20° C.) to 300° C., preferably 50 to 200° C. in consideration of heatresistance of the light emitter), volatilization is startedsimultaneously with the arrival of the droplet at the pixel electrode.Therefore, a burning step can be finished simultaneously with ejectionof a droplet to another pixel. Of course, the solvent is always made tobe volatilized from the droplet until the arrival of the droplet at thepixel electrode by the above-described method, and besides, the pixelelectrode is previously heated, whereby further improvement in filmquality can be attained.

As to the solvent with a high boiling point, NMP (N-methyl pyrrolidone),DMF (dimethylformamide), DMSO (dimethyl sulfoxide), HMPA(hexamethylphosphoramide), and other polar solvents may be used.Further, as the solvent with low polarity, there may be used an aromaticsolvent like alkylbenzene (in particular, preferably long-chainalkylbenzene like dodecylbenzene) such as xylene. For example, there canbe used a solvent in which tetralin and dodecylbenzene are mixed witheach other in a 1:1 ratio.

Note that the present invention can be implemented for both themanufacture of a passive matrix light emitting device and themanufacture of an active matrix light emitting device, and there is noparticular limitation placed on the form of the light emitting device.Further, not only an organic compound but also an inorganic compound canbe applied to the light emitting material. In particular, the presentinvention is effective for the case where organic compounds arelaminated because the burning step is not particularly required afterthe solution application.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIGS. 1A and 1B are sectional views of a solution applying device usedfor implementing the present invention;

FIGS. 2A and 2B are sectional views of a solution applying device usedfor implementing the present invention;

FIGS. 3A and 3B are sectional views of a solution applying device usedfor implementing the present invention;

FIG. 4 is a sectional view of a container for equipping the solutionapplying device used for implementing the present invention with asolution containing a light-emitter composition;

FIGS. 5A to 5C are views showing a method of manufacturing a lightemitting device according to the present invention;

FIGS. 6A and 6B are a top view and a sectional view each of which showsa pixel structure of a light emitting device obtained by implementingthe present invention, respectively;

FIGS. 7A and 7B are a top view and a sectional view each of which showsa pixel structure of a light emitting device obtained by implementingthe present invention, respectively;

FIG. 8 is a top view of a manufacturing device used for implementing thepresent invention;

FIGS. 9A and 9B are a top view and a side view of a manufacturing deviceused for implementing the present invention, respectively;

FIGS. 10A and 10B are a top view and a side view of a manufacturingdevice used for implementing the present invention, respectively;

FIGS. 11A to 11D are views showing a method of manufacturing a lightemitting device according to the present invention;

FIGS. 12A and 12B are sectional views of a solution applying device usedfor implementing the present invention;

FIG. 13 is a top view of a manufacturing device used for implementingthe present invention;

FIGS. 14A to 14C are views showing an outer appearance of a lightemitting device obtained by implementing the present invention; and

FIGS. 15A to 15H are diagrams of examples of electronic devices each ofwhich is equipped with the light emitting device obtained byimplementing the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1

An embodiment of the present invention will be described with referenceto FIGS. 1A and 1B. FIG. 1A shows a state obtained immediately after asolution containing a light emitting material is ejected, and FIG. 1Bshows a state in which, after the light emitting material reaches ananode or a cathode, a thin film (light emitting layer) is formedthereon.

In FIG. 1A, reference numeral 101 denotes an anode or a cathode; 102denotes an insulator that defines each pixel; and 103 denotes a carrierinjecting layer. The carrier injecting layer 103 is a hole injectinglayer if 101 corresponds to the anode, or is an electron injecting layerif 101 corresponds to the cathode. Further, reference numeral 104denotes an enlarged head portion in a device for performing applicationof a solution (hereinafter, referred to as solution applying device),and an internal structure of the head portion is partially shown. Thehead portion 104 includes plural ejection portions 105 a to 105 c eachhaving a function of ejecting a solution containing a light emittingmaterial. The ejection portions 105 a to 105 c are respectively providedwith piezoelectric elements (piezo elements) 106 a to 106 c. Further,the ejection portions 105 a to 105 c are respectively filled withsolutions 107 a to 107 c each containing the light emitting material.

Here, the solution 107 a containing the light emitting material containsa light emitting material that emits red light, the solution 107 bcontaining the light emitting material contains a light emittingmaterial that emits green light, and the solution 107 c containing thelight emitting material contains a light emitting material that emitsblue light. These three kinds of light emitting materials constitute apixel that emits red light, a pixel that emits green light, and a pixelthat emits blue light, respectively. These three pixels are treated as apixel unit.

Note that only one ejection portion for each of R (red), G (green), andB (blue) is explained in FIG. 1A, but plural ejection portions (nozzles)can be arranged parallelly. Taking throughput into consideration, it isthe most desirable that the ejection portions corresponding to thenumber of pixels for one row or column of a pixel portion are arranged.

Further, the most characteristic point in the present invention is thata space 108 between the head portion 104 and the anode or cathode 101 ismaintained under reduced pressure, that is, at a pressure lower than anatmospheric pressure. Specifically, the pressure is 1×10² to 2×10⁴ Pa(preferably, 5×10² to 5×10³ Pa) in an inert atmosphere, and is 1 to5×10⁴ Pa (1×10² to 1×10³ Pa) in vacuum. The solutions 107 a to 107 ceach containing the light emitting material, which are respectivelyfilled in the ejection portions 105 a to 105 c, are pressurized by thechange in volume of the respective piezoelectric elements 106 a to 106 cto thereby be pushed out, and then are ejected toward the pixelelectrode 101. Then, a droplet 109, which has been ejected, travelswhile a solvent thereof is volatilized under reduced pressure, and theremaining light emitting material is deposited on the pixel electrode101. As a result, the light emitting material is depositedintermittently.

The thin film deposited as described above is kept thin in a state inwhich the solvent component is sufficiently removed even if the solventis not particularly volatilized by means of heating or the like. Thus, alight emitting layer is obtained which involves few problems ofdeterioration with time due to degassing and the like. With theabove-described structure, a burning step or the like is not requiredeven after the application of the solution, the throughput can besignificantly improved, and also, deterioration of the light emittingmaterial itself due to heating can be avoided. Note that, thecharacteristic of the present invention is that the burning step is notrequired. However, even in combination with a burning step such as heattreatment in vacuum, an effect of the present invention is not impairedthat the light emitting layer with little degassing, in which thesolvent component has been sufficiently removed, can be obtained.

Therefore, as shown in FIG. 1B, a light emitting layer 110 a that emitsred light, a light emitting layer 110 b that emits green light, and alight emitting layer 110 c that emits blue light are formed. Thereafter,a carrier transporting layer, a carrier injecting layer, and the likeare formed as the occasion demands. Then, an opposing electrode (cathodeagainst anode, anode against cathode) is provided. Consequently, a lightemitting element is completed.

Embodiment 2

This embodiment gives an example in which: application of a solution isnot performed through ejection of droplets; and a gel solution havingviscosity to some extent is applied. FIG. 2A shows a state in whichejection of a solution containing a light emitting material is beingperformed, and FIG. 2B shows a state in which the ejection of thesolution containing the light emitting material is stopped. Note thatthe description of Embodiment 1 may be referred to for the samereference symbols as those used in FIGS. 1A and 1B.

In this embodiment, as shown in FIG. 2A, a head portion 204 of asolution applying device includes plural ejection portions 205 a to 205c each having a function of ejecting a light emitting material. Theejection portions 205 a to 205 c are respectively provided withpiezoelectric elements (piezo elements) 206 a to 206 c. Further, theejection portions 205 a to 205 c are respectively filled with solutions207 a to 207 c each containing the light emitting material. At thistime, similarly to FIG. 1A, the solution 207 a containing the lightemitting material contains a light emitting material that emits redlight, the solution 207 b containing the light emitting materialcontains a light emitting material that emits green light, and thesolution 207 c containing the light emitting material contains a lightemitting material that emits blue light.

Incidentally, in this embodiment, the viscosity of the solutions 207 ato 207 c each containing the light emitting material is adjusted to alevel higher than that of the viscosity of the solutions 107 a to 107 ceach containing the light emitting material in Embodiment 1. Theadjustment is performed in order that the solution containing the lightemitting material is continuously applied. As a result, the lightemitting material is continuously deposited. Further, as shown in FIG.2A, when being applied, the solutions 207 a to 207 c each containing thelight emitting material are pressurized by an inert gas such as nitrogento be pushed out in a state in which the piezoelectric elements 206 a to206 c are pushed downward.

Note that, as to the solutions 207 a to 207 c each containing the lightemitting material, volatilization of a solvent in each solution startsimmediately after the solution goes out of an ejection opening, thevolume of the solution is gradually reduced, and finally, the solutionreaches the pixel electrode 101. Most of the solvent has beenvolatilized at about the time the solution reaches the pixel electrode101, and the remaining light emitting material is deposited, whereby alight emitting layer is formed. Of course, an atmosphere of the space108 is maintained under reduced pressure as in Embodiment 1.

Further, as shown in FIG. 2B, when the application of the solutions 207a to 207 c each containing the light emitting material is to be stopped,the pressurization with the inert gas is stopped, and also, thepiezoelectric elements 206 a to 206 c are pushed upward (in an arrowdirection). From this, the solution containing the light emittingmaterial comes a little into an inner portion with respect to theejection opening, and thus, drying of the solution can be avoided.

Further, the space 108 is kept in a solvent atmosphere at this time,whereby drying of the solutions 207 a to 207 c each containing the lightemitting material at the ejection opening can also be avoided. Inaddition, the example is shown in which the solution is guided into theejection opening by using each of the piezoelectric elements 206 a to206 c in this embodiment. However, the same can also be realized bykeeping the space 108 in a pressurized state.

As a result, as shown in FIG. 2B, a light emitting layer 210 a thatemits red light, a light emitting layer 210 b that emits green light,and a light emitting layer 210 c that emits blue light are formed. Thelight emitting layer thus formed is kept thin in a state in which thesolvent component is sufficiently removed even if the solvent is notparticularly volatilized by means of heating or the like. Thus, thelight emitting layer is obtained which involves few problems ofdeterioration with time due to degassing and the like. With theabove-described structure, a burning step or the like is not requiredeven after the application of the solution, the throughput can besignificantly improved, and also, deterioration of the light emittingmaterial itself due to heating can be avoided.

Note that, the characteristic of the present invention is that theburning step is not required. However, even in combination with aburning step such as heat treatment in vacuum, an effect of the presentinvention is not impaired that the light emitting layer with littledegassing, in which the solvent component has been sufficiently removed,can be obtained,. Thereafter, a carrier transporting layer, a carrierinjecting layer, and the like are formed as the occasion demands. Then,an opposing electrode (cathode against anode, anode against cathode) isprovided. Consequently, a light emitting element is completed.

Further, the present invention can be implemented for both themanufacture of a passive matrix light emitting device and themanufacture of an active matrix light emitting device, and there is noparticular limitation placed on the form of a light emitting device.Further, not only an organic compound but also an inorganic compound canbe applied to the light emitting material. In particular, the presentinvention is effective for a case where organic compounds are laminatedone on another since the burning step is not particularly required afterthe application of the solution.

Embodiment 3

Another embodiment of the present invention will be described withreference to FIGS. 3A and 3B. FIG. 3A shows a state which is obtainedimmediately after the arrival, at an anode or cathode, of a droplet ofan ejected solution containing a light emitting material, and FIG. 3Bshows a state in which: the light emitting material is burned on theanode or cathode, as a result of which a thin film (light emittinglayer) is formed thereon. Note that a solution applying device in FIGS.3A and 3B is the same as that described with FIGS. 1A and 1B, and thedescription of Embodiment 1 may be referred to for the same referencesymbols as those used in FIGS. 1A and 1B.

In FIG. 3A, the ejection portions 105 a to 105 c including thepiezoelectric elements (piezo elements) 106 a to 106 c are filled withsolutions 307 a to 307 c each containing a light emitting material,respectively. In the solutions 307 a to 307 c each containing the lightemitting material, light emitting materials that respectively emit redlight, green light, and blue light are used as dissolved substances, anda solvent having a high boiling point is used (Incidentally, a solvent,which is volatilized at a room temperature (typically, 20° C.) to 300°C., preferably 50 to 200° C., is preferable.). Therefore, the solutions307 a to 307 c each containing the light emitting material are extremelydifficult to dry.

The solutions 307 a to 307 c each containing the light emitting materialare pushed out by the piezoelectric elements 106 a to 106 c to beejected from the plural ejection portions 105 a to 105 c. Referencenumeral 309 denotes a pool obtained immediately after the solutionreaches the anode or cathode 101. Of course, the space 108 between thehead portion 104 and the anode or cathode 101 is maintained underreduced pressure, that is, at a pressure lower than an atmosphericpressure. Specifically, the pressure is 1×10² to 2×10⁴ Pa (preferably,5×10² to 5×10³ Pa) in an inert atmosphere, and is 1 to 5×10⁴ Pa (1×10²to 1×10³ Pa) in vacuum.

At this time, the anode or cathode 101 is heated at a room temperature(typically 20° C.) to 300° C., preferably 50 to 200° C. As to the pool309 obtained immediately after the arrival of the solution at the anodeor cathode 101, volatilization of the solvent is started from the pointof time of the arrival. Note that, although the description is made onlyfor pixels for one line in FIG. 3A, pixels for plural lines are arrangedparallelly in an actual pixel portion, and the solutions 307 a to 307 ceach containing the light emitting material are ejected sequentially tothe respective pixels. Therefore, a fixed time is needed for applicationto all the pixels. In this embodiment, a burning step is completed bymaking use of the fixed time.

The burning step is substantially completed for the deposited thin filmat the point of time when the application to the whole pixel portion isended. A process time can be significantly reduced compared with aconventional method although the burning step itself is performed. Thus,as shown in FIG. 3B, a light emitting layer 310 a that emits red light,a light emitting layer 310 b that emits green light, and a lightemitting layer 310 c that emits blue light are formed. Thereafter, acarrier transporting layer, a carrier injecting layer, and the like areformed as the occasion demands. Then, an opposing electrode (cathodeagainst anode, anode against cathode) is provided. Consequently, a lightemitting element is completed.

Note that the same effect of the structure in this embodiment, in whichthe whole pixel portion that becomes a portion to be formed is heated inthe application of the solution containing the light emitting materialprepared with the solvent having a high boiling point by the ink jetmethod, can be obtained also when being applied to the solution applyingdevices with the structures of both Embodiment 1 and Embodiment 2.

Embodiment 4

This embodiment will describe a technology for filling a solutioncontaining the light-emitter composition shown in Embodiments 1 and 2without exposing it to the open air when the solution is filling in ahead portion.

FIG. 4 is a sectional view of a container (canister) for preserving(storing) the solution containing the light-emitter composition in thesolution applying device. It is desired that the container 351 is madefrom a material having airtightness and, particularly, having asufficiently large resistance against the permeation of oxygen andmoisture and is, desirably, made from a stainless steel or aluminum. Itis further desired that the inner surfaces thereof are finished like amirror surface. As required, further, the inner surfaces and/or theouter surfaces thereof may be coated with a silicon nitride film, adiamond-like carbon film or any other insulating film permitting oxygento pass through little. This is to prevent the solution 352 containingthe light-emitter composition in the container 351 from beingdeteriorated.

Reference numeral 353 denotes an inlet port for introducing nitrogen, arare gas or any other inert gas into the container 351, and throughwhich the inert gas is introduced to pressurize the interior of thecontainer. Reference numeral 354 denotes an outlet port from where thesolution 352 containing the light-emitter composition that ispressurized is sent into the head portion of the solution applyingdevice (not shown in the figure). The inlet port 353 and the outlet port354 may be formed of a material different from that of the container351, or may be formed integrally therewith.

Reference numeral 356 denotes an inlet pipe coupled to the inlet port353. To practically introduce the inert gas, an end of the inlet pipe356 is coupled to the inlet port 353 to thereby introduce the inert gas.Similarly, an end of the outlet pipe 357 is coupled to the outlet port354 to drain the solution 352 containing the light-emitter composition.In the drawing, the pipes are expressed as dotted lines since they aredetachable.

For example, each of the head portions shown in embodiments 1 and 2 isattached to an extended end of the outlet pipe 357. In the case ofEmbodiment 1, the piezoelectric elements 106 a to 106 c are oscillatedin a state where the interior of the container 351 is pressurized withthe inert gas, so that the solution 352 containing the light-emittercomposition is blown out intermittently. In the case of Embodiment 2,the solution can be continuously applied so far as the interior of thecontainer 351 is being pressurized with the inert gas. When theapplication of pressure is discontinued, the solution 352 containing thelight-emitter composition ceases to blow out.

In this embodiment, further, the feature resides in that the solution352 containing the light-emitter composition is transported in a stateof being kept off the atmosphere at all times from when it is introducedinto the container 351 until when the container 351 is attached to thesolution applying device. That is, the manufacturer of the solution 352containing the light-emitter composition introduces the solution 352containing the light-emitter composition into the container 351,transports it maintaining air-tightness without exposing it to theatmosphere, so as to be directly supplied to the solution applyingdevice. This is done in view of that the light-emitter composition hasweak resistance against oxygen and moisture and is easily deteriorated.After the light-emitter composition is refined, the purity of thelight-emitter composition can be preserved until it is applied, therebycontributing to suppressing the deterioration of the light-emittercomposition and maintaining improved reliability of the light-emittingdevice.

The container of the embodiment shown in FIG. 4 is only a preferredexample for transporting the solution containing the light-emittercomposition maintaining the purity thereof, but is not to limit thecontainer that can be used in the invention.

Embodiment 5

In this embodiment, a feature resides in the use of light of a longwavelength region as means for heating entire pixel portions ofEmbodiments 3. The constitution of this embodiment will now be describedwith reference to FIGS. 5A to 5C. FIG. 5A is a top view of the heatingmethod according to this embodiment, FIG. 5B is a sectional view cutalong a line A–A′, and FIG. 5C is a sectional view cut along a lineB–B′.

In FIG. 5A, reference numeral 601 is a substrate which permits thetransmission of light having wavelengths at least longer than those ofvisible rays (typically, light having wavelengths longer than 300 nm)and on which thin-film transistors and pixel electrodes are formed. Thesubstrate 601 is conveyed by a conveyer mechanism that is not shown in adirection of an arrow 602.

A head portion 603 of the solution applying device is installed over thefront surface of the substrate 601, and the solution containing thelight-emitter composition is applied in a manner as described inembodiments 1 to 3. The light-emitter composition 604 that is applied isheated by light (hereinafter referred to as lamp light) emitted from alamp 605 installed under the back surface side of the substrate 601,whereby the solvent is volatilized (fired) to form a light emitter 606.That is, the light-emitter composition 604 that is applied is firedsuccessively by lamp light to assume the form of a thin film.

Namely, due to the motion of the substrate 601, the head portion 603 andthe lamp 605 are relatively scanned in a direction opposite to thedirection in which the substrate 601 moves. It is allowable to securethe substrate 601 and to move the head portion 603 and the lamp 605, asa matter of course. In this case, the head portion 603 is set to bescanned, first, at all times. As a result, the application of thesolution by the head portion 603 and the subsequent firing by lamp lightare effected nearly simultaneously, offering an advantage which issubstantially equal to omitting the step of firing.

Light that can be used as lamp light has a wavelength which effects theheating only without destroying the composition of the light emitter606. Concretely speaking, it is desired that light has a wavelengthlonger than 400 nm, i.e., has a wavelength longer than that of infraredrays. For example, there can be used electromagnetic waves over awavelength region of from 1 μm up to 10 cm, which is from farultraviolet rays through up to microwaves. It is particularly desired touse far ultraviolet rays (typically, wavelengths of from 4 to 25 μm)even from the standpoint of handling.

The embodiment here has dealt with an example of completing theapplication over the whole surface by simply scanning the head portion603 only one time. It is, however, also allowable to reciprocally movethe substrate 601 a plural number of times to apply the solution in anoverlapped manner a plural number of times, followed by the scanningwith the lamp 605. In this case, the lamp 605 is maintained turned offwhile the head portion 603 is scanning for the first several times and,then, the lamp 605 is energized to emit light to effect the scanning insynchronism with the last scanning of the head portion 603.

Upon the irradiation with light of a wavelength longer than those ofinfrared rays by using a source of light such as a lamp as heating meansin the step of firing, it is made possible to apply the light-emittercomposition and to fire the light-emitter composition almost at the sametime to establish a system from which the step of firing issubstantially omitted. This improves the throughput of the step ofproducing light-emitting devices.

Embodiment 6

As the light emitters described in Embodiments 1 to 5, there can beexemplified a light-emitting layer, a hole injecting layer, a holetransporting layer, a hole-blocking layer, an electron injecting layer,an electron-transporting layer, an electron-blocking layer, or a stackedlayer thereof, which may be constituted by organic compounds only or acomposite of a lamination of an organic compound and an inorganiccompound.

Accordingly, this embodiment deals with an example of using a compositeof an organic compound and an inorganic compound as a light emitter inthe light-emitting device of the invention. U.S. Pat. No. 5,895,932discloses a hybrid structure obtained by laminating organic compoundsand inorganic compounds. Namely, this patent discloses technologyaccording to which Alq₃ (tris-8-quinolinolatoaluminum complex) which isan organic compound is irradiated with ultraviolet light (wavelength of380 nm) emitted from a diode of an inorganic compound to take out lightemitted due to a phenomenon called photoluminescence. This technicalidea is radically different from that of the light emitter or compositedescribed in this embodiment.

Among the organic compounds, a high-molecular organic compound(hereinafter referred to as an organic polymer) has a high heatresistance, is easy to handle, and is used as a solute in the method offorming a film by applying a solution. This embodiment deals with theuse of a composite of these organic polymer and inorganic compound as alight emitter.

The light emitters can be formed by laminating an organic polymer and aninorganic compound according to the following four typical patterns:

-   (a) a combination of a hole injecting layer (or a hole transporting    layer) of an inorganic compound and a light-emitting layer of an    organic polymer;-   (b) a combination of an electron injecting layer (or an    electron-transporting layer) of an inorganic compound and a    light-emitting layer of an organic polymer;-   (c) a combination of a light-emitting layer of an inorganic compound    and a hole injecting layer (or a hole transporting layer) of an    organic polymer; and-   (d) a combination of a light-emitting layer of an inorganic compound    and an electron injecting layer (or an electron-transportation    layer) of an organic polymer.

Further, the light emitters can be formed by mixing an organic polymerand an inorganic compound according to the following three typicalpatterns:

-   (e) a combination of a light-emitting layer of an organic polymer    having carrier-transporting property and the organic polymer in    which an inorganic compound is mixed;-   (f) a mixture of an organic polymer having carrier-transporting    property of the same polarity (n-type or p-type) and an inorganic    compound as a light-emitting layer; and-   (g) a mixture of an organic polymer having carrier-transporting    property and an inorganic compound having carrier-accepting    property.

The above constitution (g) may be a combination of, for example, anorganic polymer having a hole-transporting property in which is mixed aninorganic compound having electron-accepting property. In this case, theinorganic compound having electron-accepting property works to receiveelectrons from the organic polymer, whence holes are generated in theorganic polymer, and the holes are transported thereby to createtransporting property.

In the above constitutions (a) to (g), a p-type semiconductor materialsuch as NiO (nickel oxide) can be used as the hole injecting layer orthe hole transporting layer of the inorganic compound, an n-typesemiconductor material such as ZnO (zinc oxide) or TiO₂ (titaniumdioxide) can be used as the electron injecting layer or theelectron-transporting layer of the inorganic compound, and ZnS (zincsulfide) or CdS (cadmium sulfide) can be used as the light-emittinglayer of the inorganic compound.

In the above constitution (b), for example, a PPV (polyparaphenylenevinylene) is used as the organic polymer, CdS is used as the inorganiccompound, and these components are formed by applying the solutionthereof. In forming CdS, in this case, fine particles of CdS of theorder of nanometers (fine particles of from several nm to several tensof nm, hereinafter the same) are applied being dispersed in a solvent.The application step of this invention may be put into practice in thiscase. It is also allowable to use the n-type semiconductor material suchas ZnO or TiO₂ instead of CdS or to use the p-type semiconductormaterial such as NiO.

In the above constitution (e), for example, a PVK (polyvinylcarbazole)is used as the organic polymer, CdS is used as the inorganic compound,and these components are formed by applying the solution thereof. Inthis case, the CdS serves as a center of emitting light. In forming CdS,fine particles of CdS are applied being dispersed in a solvent. Theapplication step of this invention may be put into practice in thiscase. It is also allowable to use an inorganic compound such as ZnSinstead of CdS. The CdS and ZnS are inorganic compounds which easilyform fine particles of the order of nanometers, and are very desirablematerials when it is a prerequisite to apply a solution thereof as inthis invention.

In the above constitution (g), further, a PC (polycarbonate) is used asthe organic polymer, a TPD (triphenyldiamine) which is a holetransporting inorganic compound and an alkoxide of Ti are mixed into thePC so as to be applied in the form of a solution. Then, the lightemitter of a mixture of PC, TPD and TiO₂ is formed by the hydrolysis andvacuum heating. In forming CdS, in this case, fine particles of CdS areapplied being dispersed in a solvent. The application step of thisinvention may be put into practice in this case.

By using various organic compounds and inorganic compounds, as describedabove, it is made possible to prepare a composite light emitter byemploying the production method of this invention.

The light emitter (composite) of this embodiment can be prepared by anyone of the methods of Embodiments 1 to 3 and Embodiment 5, and can bepreserved even by using the container of Embodiment 4.

Embodiment 7

This embodiment deals with a light-emitting device produced by puttingthe invention into practice, and is described with reference to FIG. 6.In the pixel constitution shown in FIG. 6A, reference numeral 401denotes a data signal line, 402 denotes a gate signal line, 403 denotesa power source line, 404 denotes a thin-film transistor for switching(also referred to as a switching TFT, the same holds hereinafter), 405denotes a capacitor for holding electric charge, 406 denotes a thin-filmdrive transistor (referred to as drive TFT, the same holds hereinafter)for feeding a current to the light-emitting element, and 407 denotes apixel electrode connected to the drain of the drive TFT, the pixelelectrode 407 serving as an anode of the light-emitting element.Further, reference numeral 412 is an opposing electrode which serves asa cathode of the light-emitting element.

FIG. 6B is a sectional view along A–A′. In FIG. 6B, reference numeral410 denotes a substrate which may be a glass substrate, a quartzsubstrate, a plastic substrate or any other light-transmittingsubstrate. The drive TFT 406 is formed on the substrate 410 relying upona semiconductor process. Further, an insulator 408 patterned like alattice is formed so as to cover an end of the pixel electrode 407 thatis so formed as to be connected to the drive TFT 406, and to cover atleast the drive TFT and the switching TFT.

On the pixel electrodes 407 are formed light emitters 411 a to 411 c, anopposing electrode 412 serving as a cathode, and a passivation film 413.The light emitters 411 a to 411 c stand for a carrier injecting layer, acarrier-transporting layer, a carrier-blocking layer, a light-emittinglayer, or any other organic compound or inorganic compound thatcontributes to recombining carriers, or a laminate thereof. Thelaminated structure and materials of these light emitters 411 a to 411 cmay be the known constitution and materials.

For example, there may be included an inorganic hole injecting layer(which other wise may be referred to as an inorganic hole transportinglayer) having a high resistance (resistivity of from 1 to 1×10¹¹ Ωcm) asat least one layer of the light emitter as disclosed in JP 2000-268967and JP 2000-294375. The inorganic hole injecting layer contains, asfirst components, alkali metal elements selected from Li, Na, K, Rb, Csand Fr, or alkaline earth metal elements selected from Mg, Ca and Sr, orlanthanide-type elements selected from La and Ce, and contains, assecond components, the elements selected from Zn, Sn, V, Ru, Sm and In.As at least one layer of the light emitter, further, there may beincluded an inorganic electron-transporting layer having a highresistance (resistivity of 1 to 1×10¹¹ Ωcm). The inorganic holeinjecting layer contains metal elements selected from Au, Cu, Fe, Ni,Ru, Sn, Cr, Ir, Nb, Pt, W, Mo, Ta, Pd and Co or oxides, carbides,nitrides, silicates or borates thereof. Further, main component of theinorganic hole injecting layer may be an oxide of silicon, germanium orsilicon germanium. By using a stable inorganic insulating film as partof the light emitter as described above, reliability of thelight-emitting element can be enhanced.

As the opposing electrode 412, further, there can be used an aluminumfilm containing an element belonging to the Group 1 or Group 2 ofperiodic table or a thin silver film. In this embodiment, light emittedfrom the light emitters 411 a to 411 c must be transmitted and, hence,the film thickness is desirably not larger than 50 nm. As thepassivation film 413, further, there can be used a silicon nitride film,an aluminum nitride film, a diamond-like carbon film or an insulatingfilm exhibiting high blocking property against moisture and oxygen.

In producing the light-emitting device of the above constitution, thepresent invention makes it possible to produce the light-emitting deviceat a low cost, through a simple method and featuring a high throughput,as well as to improve reliability of the light-emitting device.

Embodiment 8

This embodiment deals with a light-emitting device produced by puttingthe invention into practice, and is described with reference to FIGS. 7Aand 7B. In the pixel constitution shown in FIG. 7A, reference numeral501 denotes a data signal line, 502 denotes a gate signal line, 503denotes a power source line, 504 denotes a switching TFT, 505 denotes acapacitor for holding electric charge, 506 denotes a drive TFT, 507denotes a drain electrode of the drive TFT, and 508 denotes a pixelelectrode connected to the drain electrode of the drive TFT, the pixelelectrode 508 serving as an anode of the light-emitting element. It isdesired that the pixel electrode 508 is formed of a conductive filmwhich is transparent for the visible rays so that light emitted from thelight emitter passes therethrough and is, hence, formed of an oxideconductive film such as of an ITO (a compound of indium oxide and tinoxide) or a compound of indium oxide and zinc oxide. Further, referencenumeral 512 is an opposing electrode which serves as a cathode of thelight-emitting element.

FIG. 7B is a sectional view along A–A′. In FIG. 7B, reference numeral510 denotes a substrate which may be a glass substrate, a quartzsubstrate, a plastic substrate or any other light-transmittingsubstrate. The drive TFT 506 is formed on the substrate 510 relying upona semiconductor process. Further, an insulator 509 patterned like alattice is formed so as to cover an end of the pixel electrode 508 thatis so formed as to be connected to the drive TFT 506, and to cover atleast the drive TFT and the switching TFT.

On the pixel electrodes 508 are formed light emitters 511 a to 511 c, anopposing electrode 512 serving as a cathode, and a passivation film 513.The light emitters 511 a to 511 c stand for a carrier injecting layer, acarrier-transporting layer, a carrier-blocking layer, a light-emittinglayer, or any other organic compound or inorganic compound thatcontributes to recombining carriers, or a laminate thereof. Thelaminated structure and materials of these light emitters 511 a to 511 cmay be the known constitution and materials.

For example, there may be included an inorganic hole injecting layer(which otherwise may be referred to as an inorganic hole transportinglayer) having a high resistance (resistivity of from 1 to 1×10¹¹ Ωcm) asat least one layer of the light emitter as disclosed in JP 2000-268967and JP 2000-294375. The inorganic hole injecting layer contains, asfirst components, alkali metal elements selected from Li, Na, K, Rb, Csand Fr, or alkaline earth metal elements selected from Mg, Ca and Sr, orlanthanide-type elements selected from La and Ce, and contains, assecond components, the elements selected from Zn, Sn, V, Ru, Sm and In.As at least one layer of the light emitter, further, there may beincluded an inorganic electron-transporting layer having a highresistance (resistivity of from 1 to 1×10¹¹ Ωcm). The inorganic holeinjecting layer contains metal elements selected from Au, Cu, Fe, Ni,Ru, Sn, Cr, Ir, Nb, Pt, W, Mo, Ta, Pd and Co or oxides, carbides,nitrides, silicates or borates thereof. Further, main component of theinorganic hole injecting layer may be an oxide of silicon, germanium orsilicon germanium. By using a stable inorganic insulating film as partof the light emitter as described above, reliability of thelight-emitting element can be enhanced.

As the opposing electrode 512, further, there can be used an aluminumfilm or a thin silver film containing an element belonging to the Group1 or Group 2 of periodic table. As the passivation film 513, further,there can be used a silicon nitride film, an aluminum nitride film, adiamond-like carbon film or an insulating film exhibiting high blockingproperty against moisture and oxygen.

In producing the light-emitting device of the above constitution, thepresent invention makes it possible to produce the light-emitting deviceat a low cost, through a simple method and featuring a high throughput,as well as to improve reliability of the light-emitting device.

Embodiment 9

In this embodiment, FIG. 8 shows an example of a multi-chamber typemanufacturing device in which the steps of the formation of a lightemitter up through sealing of a light emitting element are automated. InFIG. 8, reference numeral 11 denotes a preparation chamber of asubstrate to be accepted; 12, 14 a, 18, and 24 each denote a conveyingchamber for conveying a substrate to be processed (also referred to ascommon chamber); 15, 17, and 21 each denote a delivery chamber forperforming delivery of a substrate between the conveying chambers; and29 denotes a taking-out chamber of a processed substrate. In addition,reference numeral 13 denotes a pre-processing chamber, in which cleaningof an electrode surface or adjustment of a work function is previouslyperformed before the formation of the light emitter.

Further, reference symbols 16R, 16G, and 16B each denote a film formingchamber for a light emitting layer corresponding to red color, greencolor, or blue color; 16H denotes a film forming chamber for a holeinjecting layer (HIL) or hole transporting layer (HTL); and 16E denotesa film forming chamber for an electron injecting layer (EIL) or electrontransporting layer (ETL). The present invention can be implemented byproviding the solution applying device, which is the characteristic ofthe present invention, to one or plural of the above film formingchambers. Note that a film forming chamber for spin coating may beseparately provided in the case where a spin coating method needs to beused for forming the hole injecting layer, hole transporting layer,electron injecting layer, or electron transporting layer.

Further, reference numeral 19 denotes a film forming chamber for anoxide conductive film; 20 denotes a film forming chamber for a metalfilm that becomes a cathode; and 23 denotes a film forming chamber foran insulating film that is used as a passivation film. The film formingchamber 20 is desirably a film forming chamber with a sputtering methodalthough it may be a film forming chamber with an evaporation method,since there is apprehension that a TFT and a light emitting material aredeteriorated due to radial rays such as X-rays and electron beam in thecase of evaporation.

Further, reference numeral 27 denotes a sealing substrate load chamberfor stocking a sealing substrate for sealing; 25 denotes a dispenserchamber for forming a sealing material; and 26 denotes a sealing chamberfor sealing a light emitting element through bonding of a substrate tobe processed and a sealing substrate. Since the manufacturing deviceshown in this embodiment is provided with the above sealing chamber andthe like, sealing can be performed without the light emitting elementbeing exposed to an atmosphere at all. Thus, there is provided aneffective structure in realizing a light emitting device with highreliability.

In the manufacturing device in FIG. 8, the respective chambers arepartitioned by gate valves, and can be airtightly cut off from oneanother. Further, each of the chambers is coupled with a vacuum exhaustpump. Thus, vacuum can be maintained, and also, a reduced pressureatmosphere is kept through introduction of an inert gas in each chamber.As the vacuum exhaust pump, a magnetic levitation turbo molecular pump,cryo pump, or dry pump can be used. Further, it is desirable that theinert gas to be introduced is sufficiently purified at a high level bymeans of a refiner or the like in advance.

Note that the structure of the manufacturing device shown in FIG. 8 ismerely an example, and does not limit the present invention at all. Thisembodiment shows that the solution applying device for implementing themethod of manufacturing a light emitting device according to the presentinvention can be combined with the multi-chamber type manufacturingdevice. This embodiment can also be implemented in combination with anystructure of Embodiments 1 to 8 in the case of manufacturing a lightemitting device.

Embodiment 10

In this embodiment, FIGS. 9A and 9B show an example in which thesolution applying device used in implementing the present invention iscombined with an in-line type manufacturing device in which the steps ofthe formation of a light emitter up through the formation of a cathodeare performed. Note that FIG. 9A is a top view, and FIG. 9B is a sideview.

In FIGS. 9A and 9B, reference numeral 41 denotes a load chamber forcarrying in a substrate; 42 denotes an unload chamber for taking out asubstrate; 43 denotes a film forming chamber for forming a holeinjecting layer; 44 denotes a film forming chamber for forming a holetransporting layer; 45 denotes a film forming chamber for forming alight emitting layer; 46 denotes a film forming chamber for forming anelectron injecting layer; and 47 denotes a film forming chamber forforming a metal film that becomes a cathode. An arrow 50 in the figuredenotes a conveying direction of a substrate 40, and the substrate thathas been already processed is expressed by dotted lines. At this time,the substrate 40 is conveyed in the state of being upright, that is, inthe state in which a surface (surface to be processed) thereof is inparallel with a gravitational direction.

The film forming chambers 43 to 46 are the solution applying devices forimplementing the present invention, and are provided therein with headportions 43 a, 44 a, 45 a, and 46 a, respectively. These head portionseach have the structure explained in Embodiment 1 or 2, and in each headportion, application of a solution containing an organic compound orinorganic compound and formation of a thin film are performed underreduced pressure. Of course, each head portion may be provided with aheating mechanism for heating the substrate 40 at a room temperature(typically, 20° C.) to 300° C., preferably 50 to 200° C.

Further, in FIG. 9B, a side view of the film forming chamber (lightemitting layer) 45, corresponds to the state in which the head portion,which moves along the substrate surface, is seen from the above. Anarrow 51 denotes a moving direction of the head portion 45 a. The headportion moves from one end to the other end of the substrate 40 inparallel with the substrate surface, through which the solutionapplication and the formation of a thin film are performed. Note that adistance (L) between the substrate 40 and a tip end portion (ejectionopening) of the head portion 45 a is 2 to 20 mm.

Further, at this time, nitrogen, rare gas, or other fluorine gas flowsvertically in a direction perpendicular to a sheet surface in each ofthe film forming chambers 43 to 46, and a laminar flow of an inert gasis formed between the substrate 40 and each of the head portions 43 a to46 a. At this time, the flowing inert gas can be heated instead of or incombination with heating of the substrate. Of course, vacuum can be keptwithout introduction of the inert gas.

Moreover, the film forming chamber 47 is a chamber for forming a metalfilm that becomes a cathode by a sputtering method, and the filmformation is performed while the substrate 40 passes a rectangulartarget 47 a. For example, there can be formed a metal film, whichcontains en element that belongs to Group 1 or 2 of the periodic table,such as an alloy film of aluminum and lithium. The shape of the target47 a is not limited to the above-described one. However, there can begiven, as the merit of putting the substrate 40 upright, a point thatthe usage of a target having a long, narrow shape such as a liner shape,rectangular shape, or oblong shape can both secure high throughput andreduce an area of the device.

Note that there is given, as a characteristic of the present invention,a point that a burning step or the like is not required since thesolution application and the formation of a thin film are performedsimultaneously, but a burning step such as heating in vacuum may beprovided among the film forming chambers 43 to 47. This is because it isconsidered that, when the solvent component is removed from the thinfilm such as the light emitting layer, reliability is improvedaccordingly.

Embodiment 11

In this embodiment, FIGS. 10A and 10B show an example in which thesolution applying device used in implementing the present invention iscombined with an in-line type manufacturing device in which the steps ofthe formation of a light emitter up through the sealing of a lightemitting element are performed. Note that FIG. 10A is a top view of themanufacturing device, and FIG. 10B is a side view of the manufacturingdevice.

In FIGS. 10A and 10B, reference numeral 61 denotes a load chamber forcarrying in a substrate; 62 denotes an unload chamber for taking out asubstrate; 63 denotes a film forming chamber for forming a holeinjecting layer; 64 denotes a film forming chamber for forming alight-emitting layer; 65 denotes a film forming chamber for forming anelectron injecting layer; 66 denotes a film forming chamber for forminga metal film that serves as a cathode; and 67 denotes a film formingchamber for a protection film having a passivation effect. An arrow 70in the figure denotes a conveying direction of a substrate 60, and thesubstrate that has been already processed is expressed by dotted lines.At this time, the substrate 60 is conveyed in the state of beingupright, that is, in the state in which a surface (surface to beprocessed) thereof is in parallel with a gravitational direction.

The film forming chambers 63 to 65 are the solution applying devices forimplementing the present invention, and are provided therein with headportions 63 a, 64 a, 65 a, respectively. These head portions each havethe structure explained in Embodiment 1 or 2, and in each head portion,application of a solution containing an organic compound or inorganiccompound and formation of a thin film are performed under reducedpressure. Of course, each head portion may be provided with a heatingmechanism for heating the substrate 60 at a room temperature (typically,20° C.) to 300° C., preferably 50 to 200° C.

Further, in FIG. 10B, a side view of the film forming chamber (lightemitting layer) 64, corresponds to the state in which the head portion,which moves along the substrate surface, is seen from the above. Anarrow 71 denotes a moving direction of the head portion 64 a. The headportion moves from one end to the other end of the substrate 60 inparallel with the substrate surface, through which the solutionapplication and the formation of a thin film are performed. Note that adistance (L) between the substrate 60 and a tip end portion (ejectionopening) of the head portion 64 a is 2 to 20 mm.

Further, at this time, nitrogen, rare gas, or other fluorine gas flowsvertically in a direction perpendicular to a sheet surface in each ofthe film forming chambers 63 to 65, and a laminar flow of an inert gasis formed between the substrate 60 and each of the head portions 63 a to65 a. At this time, the flowing inert gas can be heated instead heatingthe substrates or while heating the substrates. Of course, vacuum can bekept without introduction of the inert gas.

Moreover, the film forming chamber 66 is a chamber for forming a metalfilm that becomes a cathode by a sputtering method, and the filmformation is performed while the substrate 60 passes a rectangulartarget 66 a. For example, there can be formed a metal film, whichcontains en element that belongs to Group 1 or 2 of the periodic table,such as an alloy film of aluminum and lithium. The shape of the target66 a is not limited to the above-described one. However, there can begiven, as the merit of putting the substrate 60 upright, a point thatthe usage of a target having a long, narrow shape such as a liner shape,rectangular shape, or oblong shape can both secure high throughput andreduce an area of the device.

Further, the film forming chamber 67 is a chamber for forming aninsulating film that includes a passivation effect by a sputteringmethod (preferably, a high-frequency sputtering method), and the filmformation is performed while the substrate 60 passes a rectangulartarget 67 a as same as Embodiment 7. For example, there can be formed ahighly dense silicon compound film, such as a silicon nitride film andsilicon oxynitride film. The shape of the target 67 a is not limited tothe above-described one. However, there can be given, as the merit ofputting the substrate 60 upright as same as Embodiment 7, a point thatthe usage of a target having a long, narrow shape such as a linearshape, rectangular shape, or oblong shape can both secure highthroughput and reduce an area of the device.

Note that there is given, as a characteristic of the present invention,a point that a burning step or the like is not required since thesolution application and the formation of a thin film are performedsimultaneously, but a burning step such as heating in vacuum may beprovided among the film forming chambers 63 to 66. This is because it isconsidered that, when the solvent component is removed from the thinfilm such as the light emitting layer, reliability is improvedaccordingly.

Embodiment 12

Embodiment 10 and Embodiment 11 has illustrated the case where thesubstrate to be treated was conveyed in an erected state, i.e., in astate where it was conveyed with its surface to be treated in parallelwith the direction of gravity. This embodiment, however, has a differentconstitution as will be described with reference to FIGS. 11A to 11D.

FIGS. 11A and 11B are views illustrating the steps of producing thelight emitters according to this embodiment, and wherein a head portion801 of the solution applying device scans along the surface of asubstrate 800. The head portion 801 injects a solution containing thelight-emitter composition in a manner described in the embodiments 1 to3, and the light emitter 802 is formed through the step of firing. Here,the feature of this embodiment resides in that the substrate 800 isinstalled so as to be at an angle relative to a horizontal plane. Anangle which is too small or too great impairs the advantage of savingthe space of the manufacturing device. Accordingly, it is desired thatthe angle of the film-forming surface of the substrate to be treatedrelative to the horizontal plane is from 70 to 95° (and, morepreferably, from 80 to 90°).

Another feature of this embodiment is the provision of means forpreventing the injection ports of the head portion 801 from drying aftera predetermined step of application has been finished for the wholesubstrate. Namely, an accommodation portion 803 for accommodating thehead portion 801 is installed under the substrate 800, and the interiorthereof is filled with a gas obtained by volatilizing the solvent. Thegas obtained by volatilizing the solvent (gas containing the solventcomponent) is introduced through an introduction port 804, and withwhich the interior of the accommodation portion 803 is filled through aplurality of openings 805 formed in the lower part of the accommodationportion 803.

Here, “the gas obtained by volatilizing the solvent” is a solventcapable of dissolving the light emitter that is to be formed and is,desirably, the same as the solvent for a solution containing thelight-emitter composition injected from the head portion 801. The gasneeds not be limited to the same solvent, as a matter of course, and maybe suitably changed depending upon the kind of the light emitter to beformed.

Next, FIGS. 11C and 11D illustrate the state of the head portion 801 ata moment after the step of forming the light emitter has been finished.As shown in FIGS. 11C and 11D, the head portion 801 is accommodated inthe accommodation portion 803 so as to be completely concealed therein,and is exposed to the atmosphere of the solvent gas. Here, theaccommodation portion 803 may be provided with a closure portion. Afterthe head portion 801 is accommodated, therefore, the accommodationportion 803 may be covered with the closure to suppress the solventcomponent from diffusing toward the outer side. The head portion issecured by a support member that is not illustrated so as to perform thescanning operation. Therefore, the closure avoids the support member, asa matter of course.

According to this embodiment as described above, the feature resides inthat after the step of forming the light emitter has been finished, thehead portion is exposed to the atmosphere filled with the solventcapable of dissolving the light emitter that is to be formed. At theinjection portions of the head portion 801, therefore, the light-emittercomposition dissolves in the solvent, and there occurs no restrictiondue to drying. Namely, there is established a non-drying environmenteven when the injection of the light-emitter composition is interrupted.Unlike the conventional so-called ink jet method, there is no need ofcontinuing the injection of solution at all times to prevent drying,decreasing the ratio of wasteful injection and improving the utilizationefficiency of the light-emitter composition.

Note that this embodiment describes a case where the embodiment isapplied to the method of manufacturing the light-emitting device inwhich solution is applied while the substrate is kept in upright.However, it goes without saying that the technical idea that the headportion is exposed to the atmosphere filled with the solvent ingredientsso as to prevent drying after applying solutions is applicable to thecase where a substrate is vertically installed as a conventional way.

This embodiment can be combined with the manufacturing device includingthe constitution of any one of Embodiments 4 to 5 and 9 to 11. Further,this embodiment can be used to the method of manufacturing the lightemitting device including any constitution of Embodiments 6 to 8.

Embodiment 13

This embodiment deals with the constitution of the head portion of thesolution applying device used for the method of manufacturing the lightemitting device of the invention with reference to FIGS. 12A and 12B.This embodiment shows a mode in which solution is applied while asubstrate is kept in upright (corresponding to Embodiments 10 and 11).However, this embodiment can be put into practice in the case where asubstrate is vertically installed.

In FIG. 12A, a substrate 901 is supported by a susceptor 902 made from amagnetic substance, and is vertically installed (which includes aninclined installation). The head portion 903 of the solution applyingdevice is provided close to the front surface of the substrate 901. Anend of the nozzle (injection port) 904 on an enlarged scale is encircledby a dotted line 905. The interior of the nozzle has a hollow structure,and includes a core 906 secured therein, and a cap (hereinafter referredto as a magnetic cap) 908 made from a magnetic substance which iscoupled to the core 906 via a resilient member (spring in thisembodiment) 907. The outer side of the hollow structure is filled with asolution 909 containing the light-emitter composition.

The material of the magnetic cap 908 is so selected that a repulsion isproduced relative to the susceptor 902 made from a magnetic material. Inthe case of FIG. 12A, the distance X1 between the substrate 901 and themagnetic cap 908 is so selected that the repulsion does not effectivelywork between the susceptor 902 and the magnetic cap 908, the distancebeing determined depending upon the magnetic material, thickness of thesubstrate and the like. When the repulsion does not effectively workbetween the susceptor 902 and the magnetic cap 908, the magnetic cap 908is pushed by the resilient member 907 and is stuffed at the end of thenozzle 904, so that the solution 909 containing the light-emittercomposition will not be injected.

After the start of the application of solution, on the other hand, thedistance between the substrate 901 and the magnetic cap 908 is shortenedto X2 as shown in FIG. 12B. The distance X2 is the one in which therepulsion works sufficiently between the susceptor 902 and the magneticcap 908. Due to this repulsion, the magnetic cap 908 compresses theresilient member 907 to push it into the hollow structure. Then, a spaceis maintained at the end of the nozzle 904, and the solution 909containing the light-emitter composition is injected. Thus, the solution909 containing the light-emitter composition is applied onto the surfaceof the substrate 901, the solvent is volatilized under a reducedpressure, or the solvent is volatilized being heated by the substrate901 thereby to form a light emitter 910.

By forming the susceptor and the cap at the end of the nozzle by usingmagnetic substances of such a relationship that produces a repulsionrelative to each other, it is allowed to establish a constitution thatapplies the solution contained therein when they are brought close toeach other up to a predetermined distance and, hence, to maintainuniformity in the distance between the substrate and the head portion(nozzle in a strict sense). This technology is effective particularly inapplying the solution onto the substrate having rugged surfaces.

This embodiment can be combined with the manufacturing device having anyconstitution of Embodiments 4 to 5, and 9 to 12. Further, thisembodiment can be used to the method of manufacturing the light emittingdevice including any constitution of Embodiments 6 to 8.

Embodiment 14

In this embodiment, description will be made of an example, in which amulti-chamber type manufacturing device is applied to the manufacturingdevice of the light emitting device, in which conveyance and filmformation are performed in a state in which a substrate is kept upright,as shown in Embodiments 12 and 13, with reference to FIG. 13. Note thatrespective chambers are coupled with a gate valve so as to be kept in anairtight state.

In FIG. 13, a carrier 702 for conveying a substrate is provided in astock chamber 701. The stock chamber 701 is coupled with a conveyingchamber 703 through the gate valve, and the substrate mounted on thecarrier 702 is conveyed by a conveying arm 704 to be placed on asubstrate mounting base 705. At this time, the substrate is firstmounted on a pusher pin 706, and then is placed on the substratemounting base 705 by lowering the pusher pin 706.

The substrate mounting base 705 is fixed with the substrate, rises by90°, moves to the inside of a load/unload chamber 707, and delivers thesubstrate to a susceptor 700. Note that the susceptor 700 expressed bydotted lines indicates that, although the susceptor exists at theposition in substrate processing, the substrate and the susceptor moveas an integrated piece in accordance with the progress of the processand do not exist at that time.

The delivered substrate in the load/unload chamber 707 moves integrallywith the susceptor 700 along with a rail, and is conveyed to a commonchamber 708 coupled with the gate valve. A turn table 709 is provided inthe common chamber 708. When the susceptor 700 is mounted on the turntable 709, the turn table 709 is rotated, and there is selected thechamber with which the common chamber is coupled through the gate valveand in which the next processing is to be performed.

The manufacturing device in this embodiment is provided with, as thechambers in which processing is performed, a film forming chamber forforming a hole transporting layer (HTL) (HTL film forming chamber) 710,a film forming chamber for forming a light emitting layer (lightemitting layer film forming chamber) 711, a film forming chamber forforming an electron transporting layer (ETL) (ETL film forming chamber)712, and a film forming chamber for forming a conductive film with asputtering method (sputtering film forming chamber) 713. The filmforming chambers 710 to 712 for forming a light emitter are eachprovided with the solution applying device explained in Embodiment 1, 2,or 3, and each are a chamber in which film formation of a light-emittercomposition is performed through solution application of ink jet or thelike under reduced pressure. Note that the respective chambers areprovided with head portions 710 a to 712 a of each solution applyingdevice, and film formation is performed through scanning in a directionin which the head portion faces a sheet surface (that is, a directionalong the substrate surface).

Further, the film forming chamber 713 for forming a cathode with thesputtering method is provided with electrodes 714 and 715 and a target716, and these members are all have a columnar or prolate ellipsoidalshape. The substrate attached to the susceptor 700 is conveyed in anarrow direction, and film formation is performed when the substratepasses the target 716. At this time, the sputtering method may be eithera DC (direct current) sputtering method or RF (alternating current)sputtering method.

Then, the substrate (susceptor), which has already been processed in therespective chambers, returns to the load/unload chamber 707, and isreceived in the carrier 702 through the substrate mounting base 705 andthe like. From the above, the steps up through the step of the formationof the cathode of the light emitting element are completed. Note that,although the description is made of the manufacturing device forperforming the steps up through the step of the formation of the cathodein this embodiment, the number of chambers may be increased in order tocomplete formation of a passivation film (protective film) or a sealingstep with a can or the like. Further, the structure of the light emitteris not limited to the one in this embodiment. Further, the structure maybe applied to the formation of the composition as shown in Embodiment 6.In this case, the number of chambers, the processing contents of thefilm forming chambers, and the like may be changed.

Note that this embodiment may be equipped with the structures ofEmbodiments 4 and 5, and may be used for the manufacture of the lightemitting devices described in Embodiments 7 and 8. Further, as to thefilm forming chambers, the structures of Embodiments 12 and 13 may beapplied to this embodiment.

Embodiment 15

In this embodiment, the constitution of the entire light emitting deviceobtained by implementing the present invention will be described withreference to FIGS. 14A to 14C. FIG. 14A is a top view of a lightemitting device prepared by sealing a element substrate on which a thinfilm transistor is formed with a sealing material. FIG. 14B is a crosssectional view along a line of B–B′ in FIG. 14A and FIG. 14C is a crosssectional view along a ling A–A′ of FIG. 14A.

A pixel portion (display portion) 82 is mounted on a substrate 81. Inaddition, a data line drive circuit 83, gate line drive circuits 84 aand 84 b, and a protective circuit 85 are arranged on the substrate 81so as to surround the pixel portion 82. Furthermore, a sealing material86 is provided such that it surrounds these structural components. Thepixel portion 82 has light emitting elements obtained by implementingthe present invention. The sealing material 86 may be an ultravioletcuring resin, an epoxy resin, or the like. Preferably, the sealingmaterial may be a material with lowest possible hygroscopic property. Bythe way, the sealing material 86 may be formed such that it is piled upon part of the data line drive circuit 83, gate line drive circuits 84 aand 84 b, and a protective circuit 85, or may be provided such that itmakes a detour to avoid these circuits.

Furthermore, a sealing member 87 is adhered on the substrate 81 by usingthe sealing material 86 and a sealed space 88 is formed from thesubstrate 81, the sealing material 86 and the sealing member 87. Thesealing member 87 may be a glass material, a metal material (typically,a stain steel material), a ceramic material, or a plastic material(including a plastic film). In addition, sealed only by an insulatingfilm as shown in Embodiment 8 also is possible.

Furthermore, when a material which is different from the substrate 81 isused as the sealing member 87, there is a possibility of impairing theadhesion properties of the sealing material 86 as a result of thedifference between their thermal expansion coefficients. Therefore, thesealing member 87 may be preferably the same material as that of thesubstrate 81 on which the transistor is formed. In other words, it ispreferable to use a material having the same thermal expansioncoefficient as that of the substrate 81. In this embodiment, glass isused as a material of the substrate 81 and the sealing member 87. Inaddition, the sealing member 87 may be subjected to the same heathistory as that of the substrate 81 in the step of preparing a thin filmtransistor, so that their thermal expansion coefficients will be inclose agreement with each other.

The sealing member 87 has a concave portion in which a moistureabsorbent (e.g., barium oxide or calcium oxide) 89 is placed in advanceto keep the closed space 88 under clear atmosphere by adsorbingmoisture, oxygen, or the like. Thus, the sealing member 87 plays a rolein the inhibition of deterioration of an EL layer. The concave portionis covered with a small-meshed cover material 90. In addition, air andmoisture can pass through but the moisture absorbent 89 cannot.Furthermore, the closed space 88 may be filled with rare gas such asnitrogen or argon, or alternatively a resin or a liquid may be filled asfar as it is inactive.

Furthermore, on the substrate 81, a terminal part 91 for transmittingsignals to the data line drive circuit 83 and the gate line drivecircuits 84 a, 84 b is formed. In addition, data signals such as videosignals are transmitted to the terminal part 91 through a flexible printcircuit (FPC) 92. The cross sectional view of the terminal part 91 isshown in FIG. 14B, in which a wiring having a structure in which anoxide conductive film 94 is piled up on a wiring 93 simultaneouslyformed with a gate wiring or a data wiring and a wiring 95 formed towardthe FPC 92 are electrically connected to each other using a resin 97 inwhich particles of a conductive material 96 are dispersed. Here, theconductive material may be a spherical polymer compound coated with goldor silver plating.

In the present embodiment, the protective circuit 85 is placed betweenthe terminal part 91 and the date line drive circuit 83 and isresponsible for releasing a pulse signal outside when the staticelectricity is caused by sudden pulse signals and the like between them.Simultaneously, at first, a capacitor weakens a high voltage signalmomentally introduced, and other high voltage signals may be allowed toescape to the outside by a circuit constructed of a thin film transistoror a thin film diode. Alternatively, the protective circuit may beformed on other place, such as one between the pixel portion 82 and thedata line drive circuit 83, and between the pixel portion 82 and thegate line drive circuits 84 a, 84 b, for example.

Embodiment 16

The structures of the thin film transistor described in Embodiments 7and 8 all become a top-gate structure (specifically, planar structure).In each embodiment, however, a bottom-gate structure (typically, reversestagger structure) can be adopted as well.

It should be understood that the application thereof is not limited tothe thin film transistor but may be made from a MOS structure transistorformed by using silicon well. Further, instead of the thin filmtransistor, using a MIM (metal-insulator-metal) element and the likerepresented by a diode (also referred to as two terminals element) alsois possible.

In any case, when an active matrix light emitting device is produced,the primary effect of the invention will not be impaired by thestructure of switching elements such as the structure of transistors.

Embodiment 17

Electronic apparatuses can be produced by employing a light emittingdevice obtained by implementing the present invention to a displayportion therein. Examples of the electronic apparatuses can be given asa video camera, a digital camera, a goggle type display (head mounteddisplay), a navigation system, an audio reproducing apparatus (a caraudio, an audio component, and the like), a laptop computer, a gamemachine, a portable information terminal (a mobile computer, a cellularphone, a portable game machine, an electronic book, etc.), and an imagereproducing apparatus including a recording medium (specifically, anapparatus capable of processing data in a recording medium such as aDigital Versatile Disk (DVD) and having a display that can display theimage of the data). Practical examples thereof are shown in FIGS. 15A to15H.

FIG. 15A shows a television, which comprises a casing 2001, a supportingbase 2002, a display portion 2003, speaker units 2004, a video inputterminal 2005, etc. The present invention is applied to the displayportion 2003. The term television includes every television fordisplaying information such as one for a personal computer, one forreceiving TV broadcasting, and one for advertisement.

FIG. 15B shows a digital camera, which comprises a main body 2101, adisplay portion 2102, an image receiving unit 2103, operation keys 2104,an external connection port 2105, a shutter 2106, etc. The presentinvention is applied to the display portion 2102.

FIG. 15C shows a laptop computer, which comprises a main body 2201, acasing 2202, a display portion 2203, a keyboard 2204, an externalconnection port 2205, a pointing mouse 2206, etc. The present inventionis applied to the display portion 2203.

FIG. 15D shows a mobile computer, which comprises a main body 2301, adisplay portion 2302, a switch 2303, operation keys 2304, an infraredray port 2305, etc. The present invention is applied to the displayportion 2302.

FIG. 15E shows a portable image reproducing apparatus equipped with arecording medium (a DVD player, to be specific). The apparatus comprisesa main body 2401, a casing 2402, a display portion A 2403, a displayportion B 2404, a recording medium (such as DVD) reading unit 2405,operation keys 2406, speaker units 2407, etc. The display portion A 2403mainly displays image information whereas the display portion B 2404mainly displays text information. The present invention is applied tothe display portions A 2403 and B 2404. The term image reproducingapparatus equipped with a recording medium includes domestic gamemachines.

FIG. 15F shows a goggle type display (head mounted display), whichcomprises a main body 2501, display portions 2502, and arm units 2503.The present invention is applied to the display portion 2502.

FIG. 15G shows a video camera, which comprises a main body 2601, adisplay portion 2602, a casing 2603, an external connection port 2604, aremote control receiving unit 2605, an image receiving unit 2606, abattery 2607, an audio input unit 2608, operation keys 2609 etc. Thepresent invention is applied to the display portion 2602.

FIG. 15H shows a cellular phone, which comprises a main body 2701, acasing 2702, a display portion 2703, an audio input unit 2704, an audiooutput unit 2705, operation keys 2706, an external connection port 2707,an antenna 2708, etc. The present invention is applied to the displayportion 2703. If the display portion 2703 displays white characters on ablack background, power consumption of the cellular phone can bereduced.

As described above, the display device obtained by implementing thepresent invention may be used as the display portions of any electronicapparatus. The electronic apparatuses of the present embodiment may useany structure of the light emitting device shown in Embodiments 1 to 3and 6 to 8.

According to the present invention, the application of the solutioncontaining the light-emitter composition such as the organic compound orinorganic compound can be performed almost simultaneously with theformation of the thin film without particularly requiring the burningstep or the like. As a result, the throughput in the manufacturing stepsof the light emitting device can be significantly improved.

Further, the solvent component in the formed thin film is sufficientlyremoved simultaneously with the film formation. Thus, there can beavoided the defect that the light emitting layer itself is deteriorateddue to degassing after the completion of the light emitting element.Therefore, the reliability of the light emitting device can be enhanced.

1. A method for manufacturing a display device comprising: forming anelectrode over a surface of a substrate; ejecting a solution containinga light-emitter composition to the electrode; and depositing thelight-emitter composition over the electrode to form at least a layercomprising a light emitter, wherein the surface of the substrate isarranged to be oblique with respect to a horizontal plane at least inthe depositing step.
 2. A method for manufacturing a display deviceaccording to claim 1, wherein the electrode is at least one of an anodeand a cathode.
 3. A method for manufacturing a display device accordingto claim 1, wherein the depositing step is performed by an ink jetmethod.
 4. A method for manufacturing a display device according toclaim 1, wherein the light-emitter composition comprises at least oneselected from a group consisting of a light emitting material, a holetransporting material, and an electron transporting material.
 5. Amethod for manufacturing a display device according to claim 1, whereinthe display device is incorporated in at least one selected from thegroup consisting of a television, a digital camera, a video camera, alaptop computer, a mobile computer, an image reproducing apparatus, agoggle type display, and a cellular phone.
 6. A method for manufacturinga display device comprising: forming an electrode over a surface of asubstrate; ejecting a solution containing a light-emitter composition tothe electrode under a reduced pressure; and depositing the light-emittercomposition over the electrode to form at least a layer comprising alight emitter, wherein the surface of the substrate is arranged to beoblique with respect to a horizontal plane at least in the depositingstep.
 7. A method for manufacturing a display device according to claim6, wherein the electrode is at least one of an anode and a cathode.
 8. Amethod for manufacturing a display device according to claim 6, whereinthe depositing step is performed by an ink jet method.
 9. A method formanufacturing a display device according to claim 6, wherein a stateunder the reduced pressure comprises a state under an inert gasatmosphere with a pressure of 1×10² to 2×10⁴ Pa.
 10. A method ofmanufacturing a display device according to claim 6, wherein a stateunder the reduced pressure comprises a state of vacuum with a pressureof 1 to 5×10⁴ Pa.
 11. A method for manufacturing a display deviceaccording to claim 6, wherein the light-emitter composition comprises atleast one selected from a group consisting of a light emitting material,a hole transporting material, and an electron transporting material. 12.A method for manufacturing a display device according to claim 6,wherein the display device is incorporated in at least one selected fromthe group consisting of a television, a digital camera, a video camera,a laptop computer, a mobile computer, an image reproducing apparatus, agoggle type display, and a cellular phone.
 13. A method formanufacturing a display device comprising: forming an electrode over asurface of a substrate; heating the electrode; ejecting a solutioncontaining a light-emitter composition to the electrode; and depositingthe light-emitter composition over the electrode to form at least alayer comprising a light emitter, wherein the surface of the substrateis arranged to be oblique with respect to a horizontal plane at least inthe depositing step.
 14. A method for manufacturing a display deviceaccording to claim 13, wherein the electrode is at least one of an anodeand a cathode.
 15. A method for manufacturing a display device accordingto claim 13, wherein the depositing step is performed by an ink jetmethod.
 16. A method for manufacturing a display device according toclaim 13, wherein the light-emitter composition comprises at least oneselected from a group consisting of a light emitting material, a holetransporting material, and an electron transporting material.
 17. Amethod for manufacturing a display device according to claim 13, whereinthe heating step is performed from a room temperature to 300° C.
 18. Amethod for manufacturing a display device according to claim 13, whereinthe display device is incorporated in at least one selected from thegroup consisting of a television, a digital camera, a video camera, alaptop computer, a mobile computer, an image reproducing apparatus, agoggle type display, and a cellular phone.
 19. A method formanufacturing a display device comprising: forming an electrode over asurface of a substrate; ejecting a solution containing a light-emittercomposition to the electrode under a reduced pressure, whereby a solventin the solution is volatilized; and depositing the light-emittercomposition over the electrode to form at least a layer comprising alight emitter, wherein the surface of the substrate is arranged to beoblique with respect to a horizontal plane at least in the depositingstep.
 20. A method for manufacturing a display device according to claim19, wherein the electrode is at least one of an anode and a cathode. 21.A method for manufacturing a display device according to claim 19,wherein the depositing step is performed by an ink jet method.
 22. Amethod for manufacturing a display device according to claim 19, whereina state under the reduced pressure comprises a state under an inert gasatmosphere with a pressure of 1×10² to 2×10⁴ Pa.
 23. A method ofmanufacturing a display device according to claim 19, wherein a stateunder the reduced pressure comprises a state of vacuum with a pressureof 1 to 5×10⁴ Pa.
 24. A method for manufacturing a display deviceaccording to claim 19, wherein the light-emitter composition comprisesat least one selected from a group consisting of a light emittingmaterial, a hole transporting material, and an electron transportingmaterial.
 25. A method for manufacturing a display device according toclaim 19, wherein the display device is incorporated in at least oneselected from the group consisting of a television, a digital camera, avideo camera, a laptop computer, a mobile computer, an image reproducingapparatus, a goggle type display, and a cellular phone.
 26. A method formanufacturing a display device comprising: forming an electrode over asurface of a substrate; heating the electrode; ejecting a solutioncontaining a light-emitter composition to the electrode under a reducedpressure; and depositing the light-emitter composition over theelectrode to form at least a layer comprising a light emitter, whereinthe surface of the substrate is arranged to be oblique with respect to ahorizontal plane at least in the depositing step.
 27. A method formanufacturing a display device according to claim 26, wherein theelectrode is at least one of an anode and a cathode.
 28. A method formanufacturing a display device according to claim 26, wherein thedepositing step is performed by an ink jet method.
 29. A method formanufacturing a display device according to claim 26, wherein a stateunder the reduced pressure comprises a state under an inert gasatmosphere with a pressure of 1×10² to 2×10⁴ Pa.
 30. A method ofmanufacturing a display device according to claim 26, wherein a stateunder the reduced pressure comprises a state of vacuum with a pressureof 1 to 5×10⁴ Pa.
 31. A method for manufacturing a display deviceaccording to claim 26, wherein the light-emitter composition comprisesat least one selected from a group consisting of a light emittingmaterial, a hole transporting material, and an electron transportingmaterial.
 32. A method for manufacturing a display device according toclaim 26, wherein the heating step is performed from a room temperatureto 300° C.
 33. A method for manufacturing a display device according toclaim 26, wherein the display device is incorporated in at least oneselected from the group consisting of a television, a digital camera, avideo camera, a laptop computer, a mobile computer, an image reproducingapparatus, a goggle type display, and a cellular phone.
 34. A method formanufacturing a display device comprising: forming an electrode over asurface of a substrate; heating the electrode; ejecting a solutioncontaining a light-emitter composition to the electrode under a reducedpressure, whereby a solvent in the solution is volatilized; anddepositing the light-emitter composition over the electrode to form atleast a layer comprising a light emitter, wherein the surface of thesubstrate is arranged to be oblique with respect to a horizontal planeat least in the depositing step.
 35. A method for manufacturing adisplay device according to claim 34, wherein the electrode is at leastone of an anode and a cathode.
 36. A method for manufacturing a displaydevice according to claim 34, wherein the depositing step is performedby an ink jet method.
 37. A method for manufacturing a display deviceaccording to claim 34, wherein a state under the reduced pressurecomprises a state under an inert gas atmosphere with a pressure of 1×10²to 2×10⁴ Pa.
 38. A method of manufacturing a display device according toclaim 34, wherein a state under the reduced pressure comprises a stateof vacuum with a pressure of 1 to 5×10⁴ Pa.
 39. A method formanufacturing a display device according to claim 34, wherein thelight-emitter composition comprises at least one selected from a groupconsisting of a light emitting material, a hole transporting material,and an electron transporting material.
 40. A method for manufacturing adisplay device according to claim 34, wherein the heating step isperformed from a room temperature to 300° C.
 41. A method formanufacturing a display device according to claim 34, wherein thedisplay device is incorporated in at least one selected from the groupconsisting of a television, a digital camera, a video camera, a laptopcomputer, a mobile computer, an image reproducing apparatus, a goggletype display, and a cellular phone.
 42. A method for manufacturing adisplay device according to claim 1, wherein the surface of thesubstrate is arranged to be 70 to 95° with respect to the horizontalplane.
 43. A method for manufacturing a display device according toclaim 6, wherein the surface of the substrate is arranged to be 70 to95° with respect to the horizontal plane.
 44. A method for manufacturinga display device according to claim 13, wherein the surface of thesubstrate is arranged to be 70 to 95° with respect to the horizontalplane.
 45. A method for manufacturing a display device according toclaim 19, wherein the surface of the substrate is arranged to be 70 to95° with respect to the horizontal plane.
 46. A method for manufacturinga display device according to claim 26, wherein the surface of thesubstrate is arranged to be 70 to 95° with respect to the horizontalplane.
 47. A method for manufacturing a display device according toclaim 34, wherein the surface of the substrate is arranged to be 70 to95° with respect to the horizontal plane.